• Journal of the Institute of Convergence Signal Processing
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• v.5 no.4
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• pp.317-324
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• 2004

Electromagnetically coupled coaxial dipole (ECCD) array antenna with and without short-ended termination is investigated theoretically. The integral equations are derived for the structure by use of the Fourier transform and mode expansion of radial waveguide. The integrals appearing in the integral equations are evaluated along the branch cut instead of real axis for a faster convergent integral. The effects of slots and dipoles, short-ended termination length, and dielectric coating on the radiation characteristics are presented. Radiation pattern of the structure is also investigated. The results of the present method are compared with those of the commercial EM simulator and good agreement is found.

• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.2
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• pp.68-73
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• 2009

In this paper, a numerical study has been carried out to investigate the influence of volute geometries on the performance of a sirocco fan. In order to achieve an optimum volute design and explain the interactions between the different geometric configurations in the volute system, three-dimensional computational fluid dynamics and the 'design of experiment' method have been applied. Several geometric parameters, such as the volute expansion angle, the cut-off position and the bell mouth shape, are employed to improve efficiency and performance. $2^k$ factorial designs were performed to screen the most influential parameters and interactions, and showed that the cut-off position and the bell mouth shape are the most significant parameters. The optimum design was selected as a result of the response surface methodology, and effects of these parameters and their interactions were presented. From the results of computational analyses and experimental data, the performance and efficiency of the sirocco fan were successfully improved. Also, detailed effects of geometric variables of the volute system on the fan performance were discussed.

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.41-47
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• 2020

This study is a qualitative study to understand the meaning and the nature of catharsis experienced by the participants of the psychodrama group. Participants were four experts who had a long history of participating in the psychodrama group. In-depth interviews were held one by one from February to June 2018, and each interview took 1-2 hours. Data collected through in-depth interviews were analyzed using Colaizzi's phenomenological research method. The result is four categories and eight theme clusters. Intrinsic structure is represented by 'physical purification', 'psychological stability', 'cognitive insight', 'Spontaneous expansion'.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.1-8
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• 1994

In this paper, in order to apply the idea MDPSK to TCM, we use signal set expansion and set partition by phase differences. Through this we propose the trellis-coded MDPSK. And the Viterbi decoder containing branch metrics of the squared Euclidean distance of the Lth order phase difference as well as the first order phase difference is introduced in order to improve the bit error rate(BER) in the differential detection of the trellis-coded MDPSK. The proposed Viterbi decoder is conceptually same to the sliding multiple symbol dection method which uses the branch metric with the first and Lth order phase differences. We investigate the performance of the uncoded DQPSK and the trallis-coded D8PSK in additive white Gaussian noise (AWGN) through the Monte Carlo simulation under the two cases of using and not using the Lth order phase difference metric. The study shows that trellis-coded 8DPSK is an attractive scheme for power and bandlimited systems while also improving the BER performance when the Viterbi decoder is employed to the Lth order phase order difference metric. This performance improvement has been obtained without sacrificing the bandwidth or the power efficiency.

• Journal of Adhesion and Interface
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• v.6 no.4
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• pp.12-17
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• 2005

Natural fiber/phenolic biocomposites with chopped henequen fibers treated at various levels of electron beam irradiation (EBI) were made by means of a matched-die compression molding method. The interfacial property was explored in terms of interfacial shear strength measured by a single fiber microbonding test. The thermal properties were studied in terms of storage modulus, tan ${\delta}$, thermal expansion and thermal stability measured by dynamic mechanical analysis, thermomechanical analysis and thermogravimetric analysis, respectively. The result showed that the interfacial and thermal properties depend on the treatment level of EBI done to the henequen fiber surfaces. The present result also demonstrates that 10 kGy EBI is most preferable to physically modify the henequen fiber surfaces and then to improve the interfacial property of the biocomposite, supporting earlier results studied with henequen/poly (butylene succinate) and henequen/unsaturated polyester biocomposites.

• Child Health Nursing Research
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• v.8 no.4
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• pp.458-468
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• 2002

The purpose of this study was to identify metacommunicative behaviors between nurses and patients in a pediatric unit. The research method included observation using videotaping. Data were collected from December, 2001 to February, 2002. Total six nurses, and eight patients and their mothers in a pediatric unit participated in this study. The interactions were videotaped under the participants' consent. The participants were observed for total 8 hours over 2-day period. Special episodes which were identified as metacommunicative behaviors in the taped interactions were transcribed. Transcription included verbal and nonverbal interactions. Selected episodes were classified using Mitchell's definition. Each classified definitions were named, and categorized by its purpose. The results were as follows: Nineteen metacommunicative behaviors which used frequently by nurses-approaching, mediating eye level, eye contact, touching, encouraging, turnabout, mimic voice, giving choices, friendly demand, expansion, tagging, repeating and confirming, identification, reflection, baby talk, symbolization, description of acts, relaxed posture, turning away- were identified and organized into four categories. They were call for attention, facilitating response, empathy, and tension release. In conclusion, nurses in this study used metacommunicative behaviors frequently and these behaviors were effective in interacting with children. It is suggested that any educational programs to teach communication skills to nurses need to include techniques on metacommunicative behaviors. This will help nurses to be more sensitive to different characteristics of their patients.

• Journal of Ocean Engineering and Technology
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• v.22 no.3
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• pp.47-57
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• 2008

Many accidents occur on the oceans. Accidents involving ships can cause enormous damage. When an accident occurs, the cost of environmental restoration can bankrupt even a top-ranked international company. The potential damages resulting from ship accidents have resulted in many international agreements such as MARPOL, SOLAS, ISM Code, etc. The viability of damaged ships has become more and more important. A damaged ship's viability and cargo safety can be improved by a safety assessment design procedure. We consider th￡ shipbuilding industry's distributed characteristics to define a safety assessment system with software engineering-based requirements analysis. We used a distributed network-based simulation method (HLA - High level architecture), because of ease of reuse and expansion of existing components to other situations, and because it is a military standard. HLA is the standard for distributed network-based simulation in many countries including the United States, Canada, Israel, and Korea. The paper describes research to develop a prototype of a network-based safety assessment simulation system by software engineering based analysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.770-772
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• 2013

Edges on the images are widely used in preprocessing in various areas including recognition and detection of the object. As generally known edge detection methods, there is a method using mask and these methods are Sobel, Prewitt, Roberts, Laplacian operator and etc. Implementation of these existing edge detection methods is simple. However, when processing the impulse noise added images, the properties of edge detection is not sufficient. Accordingly, in order to compensate for the weakness of existing edge detection methods and to detect strong edges on the images which were damaged by impulse noise, the edge detection algorithm using transformed mask was proposed in this paper.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.738-740
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• 2017

Visible light communication is a communication method using light, and it has advantage of ensuring security in a single space as compared with RF communication. However, in the area outside the visible line of the light, communication disconnection occurs. Therefore, this paper proposes a relay module to overcome the coverage extension and communication disconnection phenomenon of visible light communication. The proposed relay module transmits and receives data of visible light communication by sequentially transmitting data packets including target ID through adjacent visible light module. Through experimentation of data transmission, we confirmed the extension of the transmission range and the data reception in the area outside the line of sight.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.3
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• pp.183-192
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• 2003

This paper presents the real-time implemented distance relay algorithm which the fault distance is estimated with only local terminal information. When a single-phase-to-earth fault on a two-parallel transmission line occurs, the reach accuracy of distance relay is considerably affected by the unknown variables which are fault resistance, fault current at the fault point and zero- sequence current of sound line The zero-sequence current of sound line is estimated by using the zero sequence voltage which is measured by relaying location Also. the fault resistance is removed at the Process of numerical formula expansion. Lastly, the fault current through a fault point is expressed as a function of the zero-sequence current of fault line, zero-sequence current of sound line, and line, and fault distance. Therefore, the fault phase voltage can be expressed as the quadratic equation of the fault distance. The solution of this Quadratic equation is obtained by using a coefficient of the modified quadratic equation instead of using the square root solution method. After tile accurate fault distance is estimated. the mote accurate impedance is measured by using such an information.